The 01 design was larger and held less. In the 02 design u can put the radiator inside. A one fan, a two fan, and if you had to have a three fan for some reason you'd just remove the cage and mount your HDDs in the slots. Also the 01 design about 1/3 a case taller for no reason, due to power box placement. The Raven 01 doesn't have any more "space" than the fortress 01 which was a true ATX case and nothing else. That's the reason i got the first fortress. The Cable management on the 02 was also better Every other use of space in general was better. However the fortress 02 had the same chassis minus all the plastic from Raven 02. lol Which is why i got the Fortress 02. Also the original raven 1 (at the time) wasn't worth the money.. and with 02 chassis (preferably the fortress to the raven) it still isn't.